Ear cannot respond to all
frequencies in an unbiased manner. Audible range of human being is commonly
quoted as from 20 Hz to 20,000 Hz, which in fact will vary with age, health, past exposure
to noises, and so forth. Ear also acts like a filter and will favour certain
frequencies over the others. Ear is most sensitive to sounds at the range of 1,000 to
5,000 Hz, and particularly at about 4,000 Hz.